implementing-pubsub-pattern

Use System.Reactive's Subject<T> wrapped in an EventAggregator class that exposes GetEvent<T>() for typed subscriptions and Publish<T>() for broadcasting events. Subscribers filter by event type using OfType<T>() and can apply operators like Where or Throttle.

Create a channel with Channel.CreateUnbounded<T>() or Channel.CreateBounded<T>(), write messages via Writer.WriteAsync, and consume them with await foreach over Reader.ReadAllAsync. Register the channel, reader, and writer as singletons in the DI container.

Channels suit producer-consumer scenarios with built-in backpressure and are part of the BCL with a low learning curve. Rx.NET fits event stream processing with rich operators like Throttle, Buffer, and Retry, but requires a NuGet dependency and steeper learning.

Every Subscribe() call returns an IDisposable that must be disposed when no longer needed. Store the subscription and call Dispose() during cleanup, and dispose the Subject itself when the aggregator is shut down.

Use Channel.CreateBounded with BoundedChannelOptions to cap buffer size. Set FullMode to Wait to block writers, or DropOldest to discard old messages, preventing unbounded memory growth when consumers fall behind.

No, Subject<T> is not thread-safe by default. If multiple threads publish concurrently, wrap the subject with Synchronize() to serialize OnNext calls, or use Channels which are thread-safe by default.